advice on 1,500 ft. undergound?

nancykOctober 25, 2013

I would like to have an electric opening gate at the end of our driveway. We have not decided on a gate yet, tho it would be 14 ft wide and more-than-likely a swing gate and not real heavy. Operator is around 1/2 hp, with a programmable timer to shut the gate at night and open it in the morning. Running underground to the gate is around 1,500 ft. from an existing panel. Solar is an option but not preferred. I met with the electric company, to put in a separate meter, that would be at least $500, plus lots of messy wiring and an added pole, and another monthly bill.
We can rent a ditch-witch and lay the wire. I have priced 10-2 underground in a 1,000 and 500 ft. roll but our local electric supply suggested that 1,500 ft. is too much of a distance for 10-2(no one else has mentioned this before, not even 2 gate installing companies who have come by to give me an estimate on doing the work). Aluminum wire was suggested instead of copper. We have run aluminum wire to the barn(600 ft.) to run electric fencer, hot water heater, lights, with no problems.
We must be missing something obvious, Any suggestions as to alternatives would be appreciated. There is no electrical inspection for something like this so I am not too concerned with necessarily going by the book. This opener will not get a lot of use.

Get together all the specifications of the power requirements for your equipment and have a knowledgeable person calculate the voltage drop. All licensed electricians had to know how when they took their exam, but many never did the calculations again. Intuitively, I think your idea as presented will not work. But the solar may prove to be your best solution.
For a separate meter, the monthly charge will be $20 to $40 depending on which rate schedule they use. That really adds up over 10 years or more.
Another possibility to calculate is to run 240 volts to the gate and use a transformer at the gate to step down to 120 volts for the equipment. That will divide the calculated 120 volt loss by 4-- very significant. And 110 volts at the gate will operate it OK since operation is intermittent. Motors do not like significant undervoltage.
And if it was on my premises, I might use a transformer to step up to 480 volts at the house, then step down at the gate to 120 volts. Some cables are rated for only 300 volts and some may be rated for 600 volts. Do not exceed the voltage rating on the cable. You might not want to use this technique.

Thanks so much for inputs.
Just to clarify, the 1,500 feet distance is across a hayfield from an adjoining building to our home, this building has a panel in it. If we went from our home down the graveled driveway, not paved if that concerns Petey, the distance would be 1,700 feet.

The code recommends no more than a 5% voltage drop from the main panel to the equipment. Go to the third calculator down. For 120V single phase and 9.8 amps., the wire would be #2 copper or 1/0 aluminum.

Can you find a battery operated gate with a trickle charger? It would be basically a solar gate with a trickle charger instead of solar panels. A 12V, 1/4A trickle charger would require a 240V, 1.25A feed. That's #14 copper wire.

The UF-B cable I checked is rated for 600 volts. That makes the step up idea more feasible. A vibratory cable plow could install it.
I was just posting off the top of my head in the first post. Dream up lots of scenarios, then discard the ones not worthy of consideration.

" that's a darn long way to trench"
yes it is. in the past we trenched that distance to put in city water. The concern with doing the electric this way is putting the wire inside pipe for that distance. Certainly doable but a solar operator could really simplify things. Though it may not allow us to shut the gate from the house.

UF (Underground Feeder) cable is not made to be put inside pipe. It is made to lay in the bottom of a trench. The trench needs to be greater than 24 inches deep. So that the cover, from the top of the cable to grade, is a minimum of 24 inches.

Grey PVC schedule 80 pipe is used for physical protection. It is sleaved over the UF, anywhere the UF is visible, and to a depth of 18 inches as it passes into the ground.

Individual conductors (wires) are made to be pulled through pipe. A straight conduit body is glued approximately every 238 feet. That way a 240 foot fish tape can pull the wires along through each section.

An electric gate isn't going to offer any more security than a manual one will and will cost a great deal to implement. Seems like getting in and out of the car and manually opening the gate would be the easiest solution. Especially for something that will not get a lot of use. Really, how hard is it to do that?

Not hard at all. We have been doing just that for 30 years.
One reason my husband wanted to start shutting the gate at night, and would like to do it remotely instead of physically driving out every night, is last year 2 men drove back at 8 o'clock at night and I foolishly answered the door. To make a long story short, all ended well but neither I nor my husband were pleased with the situation. A closed gate could have been a first line of defense. At present the gate is a tubular typical farm-type gate. We close and lock it when we both leave our premises.

So you close the gate when you come home, and part of your locking up nightly routine is a bit of useful exercise to walk down and make sure that's done before you retire, just like checking the locks on your doors. That makes a lot more sense than spending a lot of money to do something that really won't keep intruders out if they really want in. Spend that money on an alarm system instead, with a driveway alarm included. Heck, just a driveway alarm can be done for under $500, with a camera. Do that 500 feet from the house rather than trying to run electrical all the way down to the property entrance.

Also check with your insurance about coverage and options so the FD can through in case of fire. I know some that have strobe sensors that will automatically open at the flash rate just like traffic signals. Some insurance companies will give you the finger if there is a house fire and the FD could not access the property. Also in a storm and power outage situation or outage because of fire the 12v solar/trickle charger is the best option. I would go solar 12v with maybe a small 400 to 600 watt wind turbine with a marine battery and also could easily run some LED lighting also. For the price of trenching anything that far a person can buy many other nice dependable alternatives. I know there are some remote opener options that are RF that could reach that far and probably still much cheaper than running and maintaining a 1500 foot cable. I have ran cat5 1000' for internet to a farm building and granted lost a lot of 'speed' but it is still better than nothing and very usable.

I just spent 30 seconds and found a gate opener that might work.

Think outside the box... I would call your local FD and see what they recommend or how they handle such situations.. then consider calling your insurance provider and go from there.